The original building, opened in 1848, and the first Catholic Cathedral in the UK since the Reformation, was the work of the great Victorian Architect, Pugin. Although much of the Cathedral was badly bombed in 1941 during the Second World War, a great deal of his design remains, and is incorporated into the rebuilt Cathedral, which was re-opened in 1958.

St. George's is the Mother Church of the Archdiocese of Southwark, which covers the actual Diocese of Southwark (South London, North Surrey, and Kent), and also the Dioceses of Arundel and Brighton, Portsmouth, and Plymouth.

The Cathedral occupies an historic site close to the Imperial War Museum, a few minutes walk from London's South Bank and the Thames, Westminster Bridge, the London Eye, and landmarks such as St Thomas' Hospital and Waterloo Station. It serves a lively and cosmopolitan community from all over London, and has a strong parish identity in addition to its role as a Cathedral. For example, the vibrant Latin American community is served with a Spanish Mass every Sunday at 1pm, delivered completely in the Spanish language. On top of this, every Mass is attended by people of different ethnicities and ages, ranging from African to Asian to European. The Cathedral is proud to be a religious home to all these audiences.